SSL Certificate Checker.
Check the HTTPS certificate of any website: when it expires, who issued it, whether browsers trust it, and whether it covers the name you are visiting.
100% free, no sign-up. To stop automated scanning, each browser can run up to 10 scans per tool every 3 hours; only that count is kept (privacy).
What Is an SSL Checker?
An SSL checker connects to a website over HTTPS and reads the certificate the server presents. The certificate is what lets a browser show the padlock: it proves that the site is the one named in the address bar and allows the connection to be encrypted.
The check shows who the certificate was issued to, the company that issued it, the dates it is valid between, the names it covers, its key type and size and the TLS version that was agreed. It also tests what a browser tests: is the certificate trusted, is it in date and does its name match the site?
SSL is the older name. The modern protocol is TLS, but people and certificate sellers still say SSL, so this tool uses both words.
A Certificate Check in One Screen.
The tool connects to the site on port 443 like a browser does, and reports what it finds, including problems that make visitors see a warning.
Expiry and days left
The valid-from and valid-until dates, with a warning when fewer than 30 days remain, so a certificate never expires by surprise.
Trusted and matching
Whether browsers would trust the certificate, and whether the name you typed is one of the names it covers.
Key and TLS version
The key type and size, the signature, the TLS version and cipher the server chose.
Names covered
Every domain name the certificate is valid for, including wildcard names such as *.example.com.
Common Problems and Fixes.
These are the certificate problems that make visitors see a warning.
The certificate has expired
Renew it at once, because visitors see a full-page warning. If you use Let's Encrypt or AutoSSL, check that renewal runs and that the domain still points to the server.
The name does not match
The certificate does not cover the address you typed, for example www versus the bare domain. Reissue it with both names, or use a wildcard certificate.
The certificate is not trusted
Usually a self-signed certificate, an unknown issuer or a missing intermediate certificate. Install the full chain file your certificate authority provided.
The TLS version is old
TLS 1.0 and 1.1 are retired and browsers reject them. Ask your host to enable TLS 1.2 and TLS 1.3.
It works in my browser but fails here
Browsers can fetch a missing intermediate certificate themselves, while other programs cannot. Install the full chain on the server so every client works.
No certificate was found on port 443
HTTPS is not set up on the server, or a firewall blocks port 443. Install a certificate and open the port.
Related Free Tools.
Frequently Asked Questions
Quick answers about this tool.
Need a Certificate Installed?
Free SSL on our hosting, or a paid certificate for a business site. Our engineers set it up and fix chain problems.